Threshold effects in strong-field photodetachment monitored by spontaneous photo-relaxation

Photodetachment of H- in a strong infrared laser field.

Negative hydrogen ions are exposed to a short infrared laser pulse of 2.15 microm wavelength and 250 fs duration. An imaging technique is used to record the energy resolved angular distribution of photoelectrons. The energy spectrum reveals at least three excess photon detachment channels. A quantum interference effect, resulting in an unusual dependence of the angular distribution on the elect...

High-resolution threshold photodetachment spectroscopy of OH

Relative photodetachment cross sections for rotational thresholds of the hydroxide anion were measured using a coaxial laser-ion beam spectrometer. The thresholds correspond to transitions from the J51 and J52 states of X S OH to the J53/2 state of X P3/2 OH. Best fits of the data give cross sections that scale with energy above threshold as (E2E th) 0.1860.06 and (E2E th) 0.2160.05 for the two...

Two-electron photodetachment of negative ions in a strong laser field.

We study the photodetachment of H-, F-, and Br- in a short laser pulse of 800 nm wavelength and 6 x 10(14) W/cm2 peak intensity. Photoelectron spectra, recorded with the use of an imaging technique, reveal a substantial contribution from the sequential process of double detachment of halogen negative ions. The saturation effect is shown to play a crucial role in this process. The role of the al...

Threshold effects in strong-field detachment of H- and F-: Plateau enhancements and angular distribution variations

Electron rescattering in above-threshold photodetachment of negative ions.

We present experimental and theoretical results on photodetachment of Br(-) and F(-) in a strong infrared laser field. The observed photoelectron spectra of Br(-) exhibit a high-energy plateau along the laser polarization direction, which is identified as being due to the rescattering effect. The shape and the extension of the plateau is found to be influenced by the depletion of negative ions ...